Physiochemical and immunochemical characterization of gamma-glutamyl transpeptidase from yolk sak tumor and ascitic hepatoma (AH-66) cells.

gamma-Glutamyl transpeptidases, purified from rat yolk sac tumor and AH-66 hepatoma cell lines resemble this enzyme system from rat kidney in their amino acid composition and antigenicity, but differ by having a higher carbohydrate content. The different carbohydrate contents resulted in the tumor cell and rat kidney enzymes having different molecular weights. Isoelectric focusing of the neuraminidase-treated enzymes showed that a substantial portion of the enzymes from yolk sac tumor and AH-66 cells shifted to a form with an isoelectric point at pH 7.4. However, a heterogeneous pattern was still found in the kidney enzyme even after extensive neuraminidase treatment.